Knock Sensor: Testing and Inspection
KNOCK SENSOR AND KNOCK CONTROL, CHECKING
Special Tools, Testers And Auxiliary Items
- VAG 1551/1552 scan tool with VAG 1551/3 adapter cable
- VAG 1598/18 test box
- Multimeter (Fluke 83 or equivalent)
- Connector test kit VW 1594
- Wiring diagram
Test Sequence
- Connect VAG 1551 scan tool (VAG 1552) and select "Engine Electronics" address word. When doing this the engine must be running at idle speed. Refer to "On-Board Diagnostics II With VAG 1551". Testing and Inspection
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to select "Read Measuring Value Block" function 08 and press -Q- button to confirm input.
Indicated on display
Read Measuring Value Block HELP
Input display group number XXX
- Press buttons -0-, -4- and -5- to input display group 045 and press -Q- button to confirm input.
Indicated on display (1-4 = Display fields)
Read Measuring Value Block 45 ->
1 2 3 4
NOTE: The check must be carried out during a test drive as knock control is not active with an engine load exceeding 3 ms.
- Perform test drive and observe specification for knock control on display (second technician necessary).
- Read the readiness code. If DTC memory has been erased, repair must be verified via appropriate display group See Readiness code, creating. Refer to "On-Board Diagnostics II With VAG 1551". Testing and Inspection
- Press -> button.
- Press buttons -0- and -6- to select "End Output" function 06 and press -Q- button to confirm input.
Evaluating Display Group 045:
Continuation
- Disconnect blue 3-pin connector -2- from Knock Sensor (KS) 1 -G61- -1-.
- Connect multimeter with test leads from VW 1594 to measure resistance between terminals 1 and 2, 1 and 3, and 2 and 3 on knock sensor connector.
Specification Infinity Ohms
If the specification is attained:
- Connect VAG 1598/18 test box to ECM wiring harness.
- Check wiring between test box and 3-pin connector for open circuit according to wiring diagram.
- Terminal 1 and test box socket 34
- Terminal 2 and test box socket 33
- Terminal 3 and test box socket 56
Resistance: max. 1.5 Ohms
- Additionally check wires for short to one another.
- Terminal 3 and test box socket 34
- Terminal 3 and test box socket 33
- Terminal 2 and test box socket 34
Specification: Infinity Ohms
If no wiring malfunction is detected:
- Loosen knock sensor and tighten again to 20 Nm (15 ft lb).
If the malfunction is still present (malfunction again in Diagnostic Trouble Code (DTC) memory):
- Replace Knock Sensor (KS) 1 -G61-
- Read the readiness code. If DTC memory has been erased, repair must be verified via appropriate display group See Readiness code, creating. Refer to "On-Board Diagnostics II With VAG 1551". Testing and Inspection